Thursday, November 17, 2011


In a recent news item, a claim was being made regarding a new sanitary agent under the name HPV that is supposed to be ideal for use by the medical and food industry. The terminology used to describe the process of disinfection was "BIO-DECONTAMINATION" giving an impression that it is not based on any chemicals but uses biotechnological technique. As it is a proprietary  product only sketchy details were offered leaving lot to guessing regarding this "innovation". The acronym HPV refers to Hydrogen Peroxide Vapor and bio-decontamination refers to killing all biological contaminants like virus, bacteria and mold. It is well known that H2O2 is a powerful oxidizing agent used commonly for room disinfection and what is new in this much touted technology is not clear.

There are hundreds of chemical substances approved for use as disinfectants world over and the most popular ones are based on their oxidizing capacity. These include Sodium Hypochlorite, Calcium Hypochlorite, Electrolyzed Water, Chloramine and Chloramine T, Chlorine Dioxide, Hydrogen Peroxide solution, Accelerated Hydrogen Peroxide solution containing surfactants and organic acids, Potassium Permanganate, Iodine, Peracetic Acid, Performic Acid and Potassium Peroxy Mono Sulfate. Hydrogen Peroxide offers several advantages when used in formulating sanitizers which include: no residue is left behind, the decomposition products are non-toxic, no preconditioning is necessary for ensuring its effectiveness and relatively less hazardous in using it. Important attributes for any disinfectant to be universally acceptable include the degree of effectiveness in achieving 100% kill of microbes, safety for the users, zero residue or non-toxicity of residues if left over, stability of the chemical(s) at room temperature, safety of storage and distribution and cost effectiveness.

H2O2 based disinfectants are increasingly becoming popular though it can be toxic if not properly handled. The principle of disinfection is based on evolution of nascent oxygen from H2O2 which can destroy almost all microorganisms on contact. The Virosil product developed in Switzerland has been an established disinfectant since a long time and the biggest advantage is its stability ( 1 year at ambient condition) though H2O2 by itself in not very stable. The product is based on 12% H2O2 and 0.01% Silver Nitrate and the nascent oxygen generated and the Silver ions present in the product act synergistically to kill all microorganisms including viruses, bacteria, fungi, yeasts, molds and algae. Its users include hospitals, pharma companies, dairies, poultry farms, cooling towers, effluent treatment, food processing, drinking water, agriculture, aquaculture. There are reports that this product is even being used as a preservative for some foods though no country has approved such a direct use. However there is natural constraint in using H2O2 directly any complex organic chemical mix that most foods are, as the nascent oxygen generated can change the flavor and other quality characteristics of the product adversely and irreversibly by oxidation. Therefore water is the only substance in which H2O2 is directly used for disinfection.

The newly developed HPV product is claimed to achieve 100% decontamination when used in solutions and said to be accepted widely within food manufacturing applications owing to a number of factors almost same as those for Virosil. Further the bioburden reduction is achieved in a relatively short time. Of course traditional manual cleaning still remains the main method of managing this critical process within the industry though its effectiveness is variable and dependent on the skill of the individual operators. Aseptic food processing is also an increasing trend in food production technology, extending product shelf life and avoiding the challenge of cold chain logistics but here also fool proof disinfection of the machinery is a prerequisite for the success of the process. Among the three products HPV solution, Virosil solution and Accelerated Hydrogen Peroxide solution, which one will become more popular ultimately will depend on the cost factor.


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